Manufacture of leather and leather-like-products.



same temperature, the alcohol Vtains 40 to 50 per cent. of alcohol, and are removed after 24.-48 hours. They are then placed, for about the same time successively in mixtures of alcohol and water of 60, 70, 80, 90 and 96 per cent. strength, whereby chiefly in the 96 per cent. alcohol only a slight increase in the amount ofwater is observed. The hides saturated with alcohol are then introduced into a vacuum still and the alcohol is distilled off at a pressure of 120 m. m. decreasing to 5 m. m. toward the end of the distillation. This radual decrease of the Dressure is to keep t e boiling point of the alcohol always at about the passing over toward the end of the distillation containing much more water than that passing over at the beginning. When maintaining these conditions the boiling point varies between 32 and ll0-45" C. The proportion by weight of the alcohol to hide substance in the prepared hide is generally on the average, 50-55'parts of alcohol to 1-1.l of prepared hide. Moreover, by the distillation, a further 10 parts of water are removed which would remain if the hide were dried in the air. In general the weight of the dry hide is 40 per lcent. of the wet prepared hide. Of the alcohol in the hide about 5 per cent. is generally lost; the rest however is recovered. The figures given in respect of the hide vary naturally within certain limits, because as is known the hides of various animals have diflierenty absorptive capacities.

We will-now describe some examples for the second step of our process.

The dry hide or skin is put in a solution of two parts of .natural asphaltum and one part of artificial asphaltum in six parts benzol and remains therein for eight to fourteen days, to enable the solution to completely permeate the hide or skin. In spe` cial cases this object may be accomplished even' in one day. Then the hide or skin is taken out of the bath cleansed with pure benzol and the benzol distilled off at atmospheric pressure, the temperature of such distillation not impairing the quality of the finished product. The product is subjected to the usual rolling or hammering and may then be used as sole leather. Good results may be obtained with a solution of one part 'of colophony and one part ceresin or paraliin in two parts of benzol, or ten parts of colophony and one part of caoutchouc or guttapercha in twenty parts of benzol. These-solutions may contain any dyestui, which will dye the product throughout. The product containing caoutchouc may be vulcanized by a process in which sulfur Vchlorid may be used. By the proper mixture of the different materials products of different properties may be obtained.

Now what we claim and desire to secure by Letters Patent is the following:

1. The process of dehydrating hides or skins, which consists in treating a hide or skin with alcohol to form a mixture of alcohol and water with the water in the hide or skin, and subse uently removing said mixture from the hide or skin by distillation in a vacuum.

2. The process of dehydrating hides or skins which consists in treating a hide or skin successively with alcoholic solutions of gradually increasing percentages of alcohol, and subsequently removin the solution retained by the hide or skin y the distillation thereof 1n a vacuum.

3. The process of manufacturing products like leather which consists in dehydrating the hides or skins and treating the same with a` solution of a material insoluble in water and forming a non-crystalline deposit after evaporation of the dissolvingfiuid.

4. The process of manufacturin -products like leather which consists in de ydrating the hides or skins and treating the same with a solution of a mixture 0f materials, Whichare insoluble in water, form a non-crystalline deposit after evaporation of the dissolvingfluid, one of the mixed materials forming a hard deposit and the other one a softer deposit.

5. The process of manufacturin products like leather which consists in de ydrating the hides or skins and treating the same with a solution of a mixture of materials, which are insoluble in water, form a non-crystalline deposit after evaporation ofthe dissolving fluid, one of the mixed materials forming a hard deposit and the other one being caoutchouc or guttapercha.

6. The process of manufacturing products like leather which consists in dehydrating the hides or skins and treating the same with a solution of a mixture of materials, which are insoluble in water, form a non-crystalline deposit after evaporation of the dissolving fluid, one of the mixed materials forming a hard depositand the other one being caoutchouc or guttapercha and vulcanizing the same afterward.

7. The process of manufacturing products like leather which consists in dehydrating the hides or skins and treating the same with a solution in 'benzol of a material which is insoluble in water and will form a non-crystalline deposit upon the evaporation of the benzol.

8. The process of manufacturing products like leather which consists in dehydrating the hides or skins and treating the same with a solution comprising a suitable arti- {icial asphalt.

9. The process of manufacturing products like leather which consists in dehydrating the hides or skins and treating the same with a solution comprising a suit-able artificial asphalt mixed with natural asphalt.

10. As a new product of,manufacture a hide or skin freed of its Water and containing artificial asphalt.

11. As a new product of manufacture a hide or skin freed of its Wat-er and contain- 15 February, 1912.

WERNER SPALTEHOLZ. KURT HARING.

Witnesses:

RUDOLPH FRICKE, EMIL RoTHs. 

